changing ph

[schizo_fish]

my ph has risen from 7.6 to 8.8+ (7.6 is tap water ph)
what could cause this? i have no fish at the moment, and have recently done a large water change.
oh, and i have a few live plants.

 

[Joviella]

Do you have any rocks or slate of any description in your tank?

 

[schizo_fish]

nope, nothing at the moment, just plants.

 

[Bignose]

did you test the water straight from the tap? Dissolved CO2 in the water supply can atrifically lower the pH for some time til the CO2 outgasses. To wit, my tap tests 7.2-7.4 but the water in my tanks is always 8.4. Set a glass out overnight and test that, or if you are impatient but an airstone in it for some time.

 

[schizo_fish]

i have a spare tank that i use for water changes, and i tested the water in there (which has been there a few days) and that had a ph of 7.6

 

[CFC]

What have you got as a substrate?

 

[Shiro337]

Also what have you got in your filter ?

 

[skimpy]

Also to find out more about your PH you need to test for GH & KH.

Try a peek at this link it may help Water Chemistry PH has GH & KH very much in the background, so these factors could be worth looking into. It has made a large difference for me, but I had the opposite problem, very soft water, very low KH and unstable PH.

Good Luck, hope it helps, or at least you find it interesting.

 

[schizo_fish]

i have a gravel substrate, and my filter is a fluval 4+ with the normal foam pads (no carbon material or anything like that)